Intravascular (IV) catheters may be used to infuse fluids into the vascular system of a patient, such as saline solution, various medicaments, total parenteral nutrition, etc. IV catheters may also be used to withdraw blood from the patient, or to monitor various parameters of the patient's vascular system.
Peripheral IV catheters may be relatively short (typically on the order of about two inches or less in length). The most common type of IV catheter is an over-the-needle peripheral IV catheter. As its name implies, an over-the-needle IV catheter is mounted over an introducer needle having a sharp distal tip. At least the distal portion of the catheter tightly engages the outer surface of the needle to prevent “peel-back” of the catheter and thus facilitates insertion of the catheter into the blood vessel. The distal tip of the introducer needle may extend beyond the distal tip of the catheter with the bevel of the needle facing up away from the patient's skin.
The catheter and introducer needle assembly may be inserted at a shallow angle through the patient's skin into a blood vessel. There are many techniques for inserting such a catheter and introducer needle assembly into a patient. In one insertion technique, the introducer needle and catheter are inserted completely into the blood vessel together. In another technique, the introducer needle is partially withdrawn into the catheter after the initial insertion into the blood vessel. The catheter is then threaded over the needle and inserted completely into the blood vessel.
In order to verify proper placement of the catheter in the blood vessel, the clinician may confirm that there is a flashback of blood in a flashback chamber. The flashback chamber is typically formed as part of a needle component or needle hub. Alternatively, the introducer needle could include a notch or opening formed along a distal portion thereof so that the blood flashback can be observed in the annular space between the introducer needle and the catheter when the catheter is transparent, or at least translucent. The clinician may then withdraw the introducer needle, leaving the catheter in place, and/or attach an appropriate device to the catheter. Such a device can include a fluid delivery device, a PRN, a deadender cap, a blood pressure monitoring probe, etc.
One common method of administering fluids into a patient's blood flow is through an intravenous delivery system. Intravenous delivery systems may include a liquid source such as a liquid bag, a drip chamber used to determine the flow rate of fluid from the liquid bag, tubing for providing a connection between the liquid bag and the patient, and an intravenous access unit, such as a catheter, that is positioned intravenously in the patient. The catheter may include a catheter adapter with one or more connectors or ports that are configured to allow “piggybacking” of intravenous delivery systems which may be used to administer medicine, among other functions.
Although typical IV catheter and introducer needle assemblies generally perform their functions satisfactorily, they do have certain drawbacks. For example, the procedure for properly placing a catheter into a patient's blood vessel can result in a significant amount of blood leakage from the catheter between the initial venipuncture and the time that an appropriate device is connected to the catheter. This blood leakage is problematic because of potential contamination to a clinician from an infected patient. This is especially worrisome because of diseases such as Acquired Immune Deficiency Syndrome (“AIDS”) which can be transmitted by the exchange of body fluids from an infected person to another person.
In order to minimize blood leakage, infusate leakage, and/or air aspiration, a self-sealing septum may be placed in the proximal end of the catheter adapter. The septum allows the introducer needle to extend through the septum and the catheter to allow the catheter to be placed into a patient's blood vessel. In addition, the septum allows the clinician to withdraw the introducer needle from the catheter and the septum, which then closes after the introducer needle has been completely withdrawn from the catheter hub. This arrangement may minimize blood leakage from the catheter adapter. The use of a septum may significantly increase the force that the clinician needs to exert on the introducer needle in order to withdraw the introducer needle from the catheter. Additionally, if the introducer needle is located in the septum for extended periods of time, the septum may take a compression set about the introducer needle preventing the septum from completely sealing once the introducer needle is withdrawn from the septum. Compression set is a material condition resulting from stress over time causing the material to maintain part or all the deformation caused by an interfacing component, even after that interfacing component is removed. Septum geometry may be designed to minimize compression set to reduce the chance of septum leakage after the introducer needle is removed, as taught in U.S. Patent Application No. US20130218082 which is hereby incorporated by reference herein in its entirety.
Once the catheter has been placed in a patients' vein, and the introducer needle has been removed, the clinician will typically secure the catheter adapter body to the patient's skin to prevent accidental removal of the catheter from the patient's vein. However, catheter adapter bodies are typically formed with rigid materials that do not conform well to the patient's skin and are not comfortable. Moreover, catheter adapter bodies formed of many different materials may be more expensive and difficult to manufacture because of their complexity. Accordingly, there is a need for soft body catheter adapters that better conform to the patient's body, improve patient comfort, and can be more securely affixed to the patient. Moreover, soft body catheter adapters may achieve a reduced cost of manufacture because they may be substantially molded from a single compliant material in an integral fashion, thus reducing the number and/or amount of different materials that may be needed during the manufacturing process.
Prior needle designs typically have distal ends with sharp bevel tips to facilitate penetration of a patients' skin and blood vessels as well as blunt shaped proximal ends that may be coupled to a suitable needle hub during assembly of the catheter system. However, blunt shaped proximal ends typically require that a lumen or slit first be formed in the septum via a “pre-slitting” process in order to allow passage of the proximal end of the needle through the septum for coupling to a suitable needle hub. This “pre-slitting” process increases manufacturing efforts and costs. Moreover, any “off-slit landing” of the proximal end of the needle on the septum during assembly may result in damage to the septum which may lead to fluid leakage.
Additionally, prior needle designs may suffer difficulties during the bonding process of the proximal end of the needle to a suitable needle hub. For example, press fitting a blunt shaped needle proximal end into a needle hub via an interference fit may result in “skiving” the interference fit region of the hub and crimping and/or gluing the needle proximal end into a needle hub may seal off the cannula of the needle disabling extended blood “flashback” capabilities which may be desirable for continuous vein confirmation (i.e., visualization of blood flowing out of the cannula of the needle as the needle is advanced into the patient's vein).